Kinase inhibitors have revolutionized cancer treatment but their use has led to drug resistance, prompting development of follow-on inhibitors for resistant tumors. Anaplastic lymphoma kinase (ALK) was discovered by Dr. Stephan Morris (Insight Genetics[unreadable] collaborator on these studies). ALK fusion genes and activating point mutations cause several cancers, and multiple pharmaceutical firms are developing ALK inhibitors. One inhibitor [unreadable] PF-02341066 (crizotinib, Pfizer) [unreadable] has entered Phase III trials and will likely receive FDA approval in 2011. The Morris group has identified a large number of ALK kinase domain mutations that confer high-level PF-02341066 resistance, which has already been reported in patients. A clinical genetic test to identify inhibitor-resistance mutations is needed to guide the development and use of next-generation ALK inhibitors for patients resistant to 1st-generation therapy. The work proposed herein will develop a clinical diagnostic assay for ALK inhibitor-resistance mutations to address this unmet need. Objective 1. Development and application of a genetic diagnostic assay to detect all known ALK inhibitor-resistance mutations using an allele-specific PCR platform. Objective 2: Demonstration and validation of the ability of the test to identify ALK mutations from both cell lines with ALK inhibitor resistance and re-biopsied lung cancer specimens from patients who developed PF-02341066 resistance.